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Surgical Management of Retroperitoneal Sarcoma

Retroperitoneal_Sarcoma

The most critical component of the treatment of Retroperitineal Sarcoma (RPS) remains the surgical excision, and the best chance for cure is at the time of primary surgery. Surgery should achieve a macroscopically complete excision of the tumor (R0 or R1), minimizing marginality, ideally through an en-bloc resection of all potentially involved structures as determined by careful preoperative imaging in combination with intraoperative findings.

Operative planning also includes the functional assessment of critical organs—eg, the function of each kidney. Contraindications to primary resection are believed to be bilateral renal involvement; encasement of the superior mesenteric artery, celiac axis, and porta hepatis; and spinal cord involvement.

When planning for surgery, it is paramount to take into consideration the histology of the RPS as well as its predicted behavior pattern, as these differ widely. Indeed, the largest transatlantic multi-institutional series identified histologic subtype as a predictor of patterns of local and distant recurrence. Moreover, analysis of a large, single-institution database demonstrated that histologic subtype is the strongest predictor of disease-specific death and affects both local and distant recurrence. Of greater interest, the patterns of contiguous organ involvement are also heavily dependent on histologic subtype.

In light of these data, surgeons oncologists should decide the extent of surgical resection in a multidisciplinary setting at a specialized center after review of imaging and pathology, given that the pattern of growth and prognostic risks vary broadly among the different histologic subtypes. For example, liposarcoma is the histologic subtype with the highest recurrence rate. In addition, it is the one with the least clear separation from normal retroperitoneal fat, given that the well-differentiated component of liposarcoma is virtually undistinguishable from normal fat. As a consequence, the extent of surgery should be aimed at removing all ipsilateral retroperitoneal fat en bloc with the mass at the price of sacrificing at least the ipsilateral kidney and colon and part of or the entire psoas muscle.

A staged approach can be followed in virtually all cases. The stages include:

A. Generous laparotomy, exploration, and retraction.

B. Division of the gastrocolic ligament, division of the transverse colon (plus distal ileum if on the right side), and assessment of the duodenum/head of the pancreas if on the right side, or body/tail of the pancreas and spleen if on the left side.

C. Liberation of duodenum/head of the pancreas if on the right side or body/tail of the pancreas and spleen and duodenojejunal junction if on the left side (when possible) and partial duodenal resection or pancreaticoduodenectomy (< 5% of right-sided retroperitoneal sarcomas) if on the right side or distal pancreatectomy and splenectomy if on the left (40%–50% of left-sided retroperitoneal sarcomas), when too adherent/invaded by the tumor.

D. Dissection of the inferior vena cava (IVC) if on the right side or aorta if on the left side, ligating ipsilateral renal vessels and other collaterals and dissection of the iliac vessels.

E. Peritonectomy, resection of the psoas muscle in the pelvis (plus rectal resection if on the left side) after identification and liberation of the femoral nerve (unless directly invaded) and possibly of the femoral cutaneous branch, while the genitofemoralis and ilioinguinal nerves are usually resected, as these lie between the tumor and the psoas fascia.

F. Section of the origin of the psoas major from the spine, sparing the roots of the femoral nerve and possibly the iliohypogastric nerve, liberation/resection of the costodiaphragmatic fold, and removal of the specimen.

Subcapsular liver dissection or partial hepatectomy are rarely needed for tumors located on the right side, whereas a complete liberation of the right liver lobe is usually of help. Similarly, sleeve gastrectomy or proximal gastrectomy is rarely required for tumors located on the left side. Finally, vascular resections (predominantly iliac vessels on either side and IVC on the right side) are required in 4% of cases.

Leiomyosarcoma and other rarer histologic subtypes such as solitary fibrous tumor are much more well-defined tumors. Their border can be clearly separated from retroperitoneal fat/structures. A wide resection is still required but not necessarily involving the adjacent organs if these are not clearly invaded.

Extended surgery may raise concern for added morbidity. A recent multi-institutional collaboration, however, found that a radical resection is safe and is associated with low 30-day mortality (1.8%). Severe complications were associated with increased age, transfusion requirements, and organ resection score, with a more pronounced risk in patients undergoing splenectomy and pancreatectomy and Whipple procedure.

Although major vascular resection (MVR) is associated with higher morbidity, vascular involvement does not preclude resection because it can be safely performed in specialized centers. MVR may be necessary either due to the origin of the RPS, as is the case for leiomyosarcoma of the IVC, or due to local invasion and involvement. Whereas multiple strategies for approaching MVR can be used, a good understanding of the vasculature and collaterals is critical prior to attempting resection and reconstruction, given that IVC resections are well tolerated if a good network of collaterals is present.

In essence, resection of RPS requires technical expertise in multiple sites throughout the abdominal and pelvic cavity, including the handling of large vessels. Single organ/site expertise is not sufficient. The ability to orchestrate a team of complementary surgical experts is critical to successful management of RPS patients. To minimize the risk of intraoperative and perioperative morbidity, RPS resection should be undertaken by surgical teams with expertise in specific aspects of the anatomy of the retroperitoneal space—for example, expertise in retroperitoneal autonomic and somatic nerves, the lymphatic system, paravertebral vessels, and organs of the gastrointestinal tract.

Required expertise also includes experience with additional procedures, such as full-thickness thoracoabdominal wall resection and reconstruction, diaphragmatic resection and reconstruction, major vascular resection and reconstruction, and bone resection. Surgical teams with these abilities, which may accrue from prior participation in multidisciplinary surgical teams, can achieve macroscopically complete tumor resection in the majority of patients.

Hepatic Hemangioma: Is There an Indication for Surgical Resection?

Hepatic hemangioma (HH) is the most common benign liver tumor. It consists of blood-filled cavities fed by the hepatic arterial circulation, with walls lined by a single layer of endothelial cells, a veritable chaotic entanglement of distorted blood vessels confined to a region as small as a few mm and as large as 10 cm, 20 cm and even 40 cm. The frequency is higher among adults, with a prevalent age at the initial diagnostic in the range of 30-50 years. Literature places the HH incidence at 0.4% to 20% of the total population. At necropsy, the frequency is of 0.4 to 7.3%, all the authors agreeing with an incidence of over 7%. The HH prevalence in the general population varies greatly, most often being discovered incidentally during imaging investigations for various unrelated pathologies. Regarding sex distribution, it seems that women are more susceptible, as confirmed by all pertaining studies, with a reported 4.5:1 to 5:1 ratio of female to male cases. Most often, HH are mono-lesions but multiple-lesions are possible; they account for 2.3% and up to 20-30% of the cases, depending on the source. At the initial diagnosis, the majority of HH measure below 3 cm in size, the so-called capillary hemangiomas; of these, only 10% undergo a size increase with time, for reasons still unknown. The next size class covers lesions between 3 cm and 10 cm in size, referred to as medium hemangiomas. Lastly, giant or cavernous hemangiomas measure up to 10 cm, with occasional literature reports of giant HH reaching 20-40+ cm in size. Location-wise they are most often found in the right liver lobe, often in segment IV, often marginal.

Operative Management

Operative intervention for liver hemangiomas remains a controversial topic. Previous studies from major hepatobiliary centres have proposed varying indications for a hemangioma resection. Findings from the present study demonstrate that operative management of symptomatic hemangiomas remains an effective therapy and can be performed with low morbidity to the patient. However, aside from abdominal symptoms, prophylactic resections in the setting of hemangioma enlargement, size, or patient anxiety is not advised as the risk of developing life-threatening associated complications is rare.

Established Complications. In the minority of cases that present as a surgical emergency due to haemorrhage, rupture, thrombosis and infarction, surgical management may be the only appropriate course of action. There is also a role for the elective surgical management of giant haemangiomata, albeit in a highly selected group of patients. As demonstrated by the data presented above, an operative approach with the objective of preventing future complications of giant haemangiomata is less easy to justify.

Diagnostic Uncertainty. Despite improvements in non-invasive imaging technology, cases of diagnostic uncertainty continue to pose a challenge. In situations where it is not possible to exclude malignancy, surgical intervention by formal liver resection may be indicated. In almost all situations, the use of percutaneous liver biopsy for the differentiation of giant haemangiomata from malignant liver lesions cannot be justified. The risks of haemorrhage as a result of biopsying a giant haemangioma are appreciable and, together with the risks of needle track seeding and intra-abdominal dissemination of a potentially curable malignancy, mean that biopsy in this setting must be avoided.

Incapacitating Symptoms. Having taken all possible steps to ensure that symptoms are attributable to the haemangioma, surgical resection may be justified on grounds of intractable symptoms. Patients with clearly defined abdominal compressive symptoms may be more likely to derive benefit from surgery than patients with non-specific abdominal discomfort, although this is not backed up by a meaningful body of evidence. Management of this group of patients is, by necessity, highly individualised. Despite apparently satisfactory surgical management, symptoms persist in approximately 25% of patients following resection of seemingly symptomatic haemangiomata.

While most people with HH show no sign or symptom, and most HH are non-progressing and do not require treatment, there is a small number of cases with rapid volumetric growth or complications, which prompt for appropriate therapy. The results of clinical and laboratory investigations to date, mostly for imaging techniques, have demonstrated that for small HH, regular follow-up is enough. For cavernous HH, the evolution is unpredictable and often unfavorable, with serious complications requiring particular surgical expertise in difficult cases. Hepatic hemangiomas require a careful diagnosis to differentiate from other focal hepatic lesions, co-occurring diagnoses are also possible.

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